1. Field of the Invention
The present invention relates to a nano-fiber material, and in particular relates to a salt rejection filtration material.
2. Description of the Related Art
Water treatment has grown in importance recently, as industries continue to expand and global warming becomes more of a problem. Several salt rejection filtration materials which may be used in seawater and wastewater have been developed. The developmental objectives of the materials are to increase salt rejection and water flux.
U.S. Pat. No. 4,828,700 discloses a membrane made of cross-linked poly methyl methacrylate. The membrane has a 9.1 GFD flux, and a 97.9% salt rejection, when tested under an operating pressure of 400 psi using 2500 ppm of salt water.
U.S. Pat. No. 5,755,964 discloses a reverse osmosis (RO) membrane, wherein the RO membrane has good wetting property by using amine compound to treat the surface of the RO membrane. The RO membrane has a 48 GFD flux, when tested under an operating pressure of 225 psi using 2000 ppm of salt water. The RO membrane exhibits high flux like nanofiltration material.
Salt rejection filtration materials are in the form of a membrane in prior art. However, in order to improve flux, the membrane needs to be operated under a high pressure. Meanwhile, fiber has advantages of high surface area, high porosity and low pressure filtration. Accordingly, if a filtration material in the form of a fiber is developed, salt rejection and water flux of filtration material may be increased.